.\" Copyright (c) 2001 Scott Long
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\"
.Dd December 15, 2005
.Dt SND_MAESTRO3 4
.Os
.Sh NAME
.Nm snd_maestro3
.Nd "ESS Maestro3/Allegro-1 bridge device driver"
.Sh SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device sound"
.Cd "device snd_maestro3"
.Ed
.Pp
Alternatively, to load the driver as a module at boot time, place the
following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
snd_maestro3_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for the ESS Maestro3 and Allegro-1 sound chips
under the PCM framework.
These chips are mostly found in laptop computers and feature an AC97 mixer,
a multi-channel sample rate converter that can mix up to four digital audio
streams in hardware, recording support, and external volume control buttons.
.Pp
The firmware for the sound processor is licensed under the GNU Public
License, and thus this driver is not included in the default
.Pa GENERIC
kernel.
.Sh HARDWARE
The
.Nm
driver supports the following audio devices:
.Pp
.Bl -bullet -compact
.It
ESS Technology Allegro-1
.It
ESS Technology Maestro3
.El
.Sh DIAGNOSTICS
The hardware volume control buttons can be connected to two different pin
sets (GPIO or GD) on the chip, depending on the manufacturer.
The driver has no way of determining this configuration, so a hint may be
used to override the default guess.
The default setting for hardware volume control assumes that GD pins
are wired to control the hardware volume.
For systems that have the GPIO pins wired to the hardware volume control
buttons, add the line
.Dq Li hint.pcm.0.hwvol_config="0"
to the file
.Pa /boot/device.hints
to override the default setting.
.Sh SEE ALSO
.Xr sound 4 ,
.Xr loader.conf 5
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 4.3 .
.Sh AUTHORS
.An Scott Long Aq Mt scottl@FreeBSD.org
.An Darrel Anderson Aq Mt anderson@cs.duke.edu
